For the first-line treatment of follicular lymphoma (FL), obinutuzumab plus chemotherapy (chemo) is cost-effective in comparison with rituximab biosimilars plus chemotherapy in the United States (J Manag Care Spec Pharm. 2021 May;27:615-624. doi:10.18553/jmcp.2021.20424).
Results from the phase 3 GALLIUM trial demonstrated improvements in progression-free survival (PFS) with obinutuzumab plus chemotherapy vs rituximab plus chemotherapy for patients with FL. Additionally, obinutuzumab plus chemotherapy was found to be cost-effective in comparison to rituximab plus chemotherapy.
‘Two rituximab biosimilars, rituximab-abbs and rituximab-pvvr, have been approved by the FDA for use in this setting. However, the cost-effectiveness of [obinutuzumab plus] chemo versus [rituximab-abbs plus] chemo and [rituximab-pvvr plus] chemo has not yet been estimated,” explained Scott J. Spencer, MPA, MA, University of Washington Institute for Public Health Genetics, and colleagues.
This study aimed to evaluate the cost-effectiveness of obinutuzumab plus chemo vs the rituximab biosimilars plus chemo for the first-line treatment of FL.
An existing Markov model comparing obinutuzumab plus chemo with rituximab plus chemo was adapted for this study. Investigator-assessed PFS and postprogression survival, drug utilization, and treatment duration data were derived from the GALLIUM trial.
Health care costs were based on Medicare reimbursements. Drug costs were average sale prices for intravenous therapies or wholesale acquisition costs for oral therapies used after progression.
The model assumed efficacy and safety of the rituximab biosimilars were the same as the rituximab arm of the GALLIUM trial.
Obinutuzumab plus chemo yielded an increase of .93 quality-adjusted life years (QALYs) compared with the rituximab biosimilars plus chemo. The total cost associated with obinutuzumab plus chemo was $191,317 compared with $164,340 for rituximab-abbs plus chemo and $169,755 with rituximab-pvvr plus chemo, resulting in incremental costs of $26,978 (95% CR = $19,781-$33,119) and $21,562 (95% CR = $14,473-$28,389), respectively.
The incremental total drug and administration costs were $32,678 for obinutuzumab plus chemo vs rituximab-abbs plus chemo and $27,263 for obinutuzumab plus chemo vs rituximab-pvvr plus chemo. Cost savings of $7,050 related to disease progression for obinutuzumab plus chemo ($56,727) were noted compared with the rituximab biosimilars plus chemo ($63,777). Incremental cost-effectiveness ratios (ICERs) were $28,879 and $23,082 per QALY gained for obinutuzumab plus chemo vs rituximab-abbs plus chemo and rituximab-pvvr plus chemo, respectively.
In probabilistic sensitivity analyses, obinutuzumab plus chemo was cost-effective at the $50,000 and $100,000 per QALY thresholds vs both rituximab-abbs plus chemo (88% and 98% probabilities of cost-effectiveness, respectively) and rituximab plus chemo (93% and 98%, respectively).
“[Obinutuzumab plus] chemo is projected to be cost-effective versus rituximab biosimilars plus chemotherapy in the United States as first-line treatment for FL, driven by increased QALYs for [obinutuzumab plus] chemo and cost savings from delayed disease progression,” concluded Mr Spencer and colleagues.—Janelle Bradley